The ability to silylate organic moieties has attracted significant attention in recent years, owing to the utility of the silylated materials in their own rights or as intermediates for other important materials used, for example, in agrichemical, pharmaceutical, and electronic material applications.
Over the past several decades, considerable effort has been allocated to the development of powerful catalyst architectures to accomplish a variety of C—H functionalization reactions, revolutionizing the logic of chemical synthesis and consequently streamlining synthetic chemistry. Accomplishing such challenging transformations can often necessitate the use of stoichiometric additives, demanding reaction conditions, complex ligands, and most notably precious metal precatalysts. Notably, the need to use precious metal catalysts for these transformations remains a fundamental and longstanding limitation.
Strategies for the synthesis of ethynylsilanes have employed strong bases or have relied on stoichiometric or catalytic transition metal species such as Pt, Zn, Au, and Ir, typically using various pre-activated organosilicon coupling partners at high temperatures. Inexpensive and commercially available hydrosilanes have been investigated, however this particular silicon source has introduced new challenges: the requisite in situ Si—H bond activation necessitates exogenous bases, sacrificial hydrogen acceptors or oxidants, and elevated temperatures (i.e., 80-120° C.). Moreover, undesired hydrosilylation of the alkyne can be competitive, further complicating catalyst and reaction design. These factors have led to important limitations in scope and practical utility. For example, substrate classes important in pharmaceuticals and natural products applications such as aliphatic amines and nitrogen heterocycles are notably absent in the aforementioned reports. Despite the inherent acidity of terminal acetylenes, the development of a mild and general stoichiometric or catalytic method for cross-dehydrogenative C(sp)-Si bond formation remains a longstanding challenge in the field.
The present invention takes advantage of the discoveries cited herein to avoid at least some of the problems associated with previously known methods.